Renishaw duo show age is just a number

David McMurtry, 71, and John Deer, 73, run a high-powered engineering business from a 19th century former woollen mill in Gloucestershire. Interview by Ruth Sunderland.

Young at heart: Renishaw's founders Sir David McMurtry and John Deer have no plans to retire

The little Gloucestershire market town of Wotton-under-Edge, nestling on the slopes of a valley, looks like an ideal backdrop for retired colonels, dotty spinsters and perhaps a genteel English murder mystery.

It's like something out of a PG Wodehouse novel, which is why you wouldn't expect to encounter two formidable captains of industry there - running a billion pound engineering and export powerhouse.

Particularly when the pair of them are gentlemen in their seventies.

But then Sir David McMurtry, 71, and John Deer, 73, are no ordinary septuagenarians.

Their business, Renishaw, manufactures industrial machine tools such as touch probes for measuring pipes and highly sensitive laser microscopes from their headquarters in Wotton with an energy many young executives would envy.

When they are not bickering affectionately like a long-married couple, that is. For they could be an older version of the Likely Lads. While McMurtry is hyperactive and voluble, Deer is the dry-humoured, quieter one.

The centre of their empire is a 19th century former woollen mill set in 26 acres of parkland just outside the town, with a view over a lake where swans glide by and peacocks strut.

McMurtry says he bought the premises from British fabric manufacturer Courtaulds Textiles in the 1980s.

They were making elastic for Y-fronts,' Deer explains.

The pair say Courtaulds was forced to sell up in Wotton because of cheap competition from China, but they don't see much chance of that fate overtaking them.

'It's never been an issue for us,' says McMurtry. Renishaw has succeeded thanks to its founders' belief in research and development, producing innovative products that can command a high price, then protecting them through patents.

McMurtry and Deer set the company on a constant cycle of improvement, so that when one product comes out of patent, another invention comes along to take its place.

McMurtry says: 'If you apply that philosophy you can keep ahead. We have done it for more than 30 years and there is no reason we can't go on.'

It's a way of thinking that sets Renishaw apart from mainstream British industry.

In the decade before the credit crunch, metropolitan sages declared British industry was irrelevant and uneconomic, but Renishaw ignored them and carried on manufacturing.

Over those same ten years, the scribblers of the Square Mile sang the virtues of cheap borrowing, but Renishaw eschewed debt.

And as scores of executives enriched themselves by selling out to foreign bidders, Deer and McMurtry refused to be dislodged from the company they built over nearly 40 years - because they love it too much.

True, they have made concessions to the cult of youth - finance director Allen Roberts and assistant chief executive Ben Taylor are only in their early sixties.

But their most senior employee, Professor Joseph Franks, an expert in tough carbon coatings, is working at 87 - and McMurtry and Deer show every sign of following that example.

Still, why Wotton? Well, despite its idyllic appearance, this has always been a working town. In days gone by, its prosperity rested on the cloth trade.

Sir Isaac Pitman, inventor of the shorthand system, lived here, and there is a streak of stubbornness and non-conformism in the locals: another famous son is the founder of the political philosophy utilitarianism, John Biddle, who died in prison for his beliefs.

McMurtry and Deer, who met when working for Rolls-Royce in Bristol in the 1970s, set up their business here for the simple reason that they liked it - even though the location baffles some overseas clients.

'One company wrote us a letter addressed to "Woman under Hedge", but it got here all right,' says Deer. Would they consider moving Renishaw overseas if it was financially advantageous?'

'The fact we are beyond retirement age shows we have no intention of going anywhere,' Deer says adamantly.

'Some are more beyond than others,' jokes McMurtry.

Do the pair of them ever fall out? 'Oh, regularly,' they chorus in unison. 'Never seriously,' adds McMurtry.

Although in cheerful mood now, they have had their share of difficult times and the pain from the recent economic crisis still seems raw. Almost 400 employees were made redundant in the darkest period Renishaw has ever gone through. McMurtry feared it might go bust.

The firm was accused of insensitivity for sending out an email asking staff to clear their desks of personal possessions ahead of the job loss announcements - and the share price went into freefall. Sales halved in just three months at the start of 2009. Fortunately, the firm rallied.

In the second half of last year, its profits rose to a record £35.5m - a five-fold increase - and it is now looking to hire 160 people.

Had Renishaw collapsed, it would have been a bitter blow for Wotton, as the company has provided work for generations of local families in the village.

It was while the pair were working for Rolls-Royce that McMurtry spotted there was a design problem measuring small fuel pipes for Concorde engines and invented the first 'touch trigger probe' over a weekend in his garage.

Before his device, the engine pipes were measured by people pushing a probe inside, and the results were just not precise enough.

McMurtry came up with a three-pronged electrical probe that triggered a signal when it came into contact with the surface of a pipe. It was capable of measuring to fractions of a micron - a millionth of a metre - and was much more accurate and consistent than the old method.

'I made one at home. My wife was well used to that sort of thing, because I had made our central heating. I made a complete boiler that was hopper-fed and had an automatic feed into the lounge. That worked very well until the hopper feed malfunctioned.'

For several years McMurtry carried on working at Rolls-Royce while getting Renishaw off the ground, with Deer looking after the commercial side.

'We were in our early 30s and I was working all over the weekend and in the evenings. I was exhausted doing two jobs,' he says.

'No, he wasn't,' Deer snorts. 'He does something in five minutes that would take other people a week.' McMurtry ignores him, and continues: 'My wife couldn't understand it because I had a good job at Rolls, so why did I want more?

'But it is not about money, it is about doing something that no one else had done before. I still invent things at home. I invented a ridiculous house,' he says, referring to his futuristic eco-mansion.

From that one-touch trigger probe, Renishaw has grown so it now has a huge portfolio of products, including measuring probes and magnetic encoders, which are used to make sure machinery moves precisely as it should in production lines ranging from food manufacturing to 3D televisions.

It has also set up a healthcare division and is a leader in a high-tech microscope method called Raman spectroscopy, which is being used in research into infertility and in quality control for solar panels.

Renishaw also makes robots for brain surgery - the first of which has been installed at the neurosurgery unit at Bristol's Frenchay hospital.

But the obvious question is what will happen to the company when they are no longer around to run it?

The pair certainly have no financial need to work - their combined 53% stake in the business is worth more than £600m - but it seems neither they, nor their long-suffering families, can imagine them doing anything else.

'It's a life, isn't it,' Deer says. 'We might die in harness or get Alzheimer's. But as long as we are healthy, we will carry on.'